1. Field
The present invention relates to an outsole for a sports shoe, especially a cross-country ski boot or telemark boot, consisting of a rear portion, which comprises a shoe heel, and a front portion, which is of slightly dish-shaped configuration, the outsole being produced so as to be continuously of relatively hard material, especially plastics, and being provided on the tread side, both in the region of the front portion and in the region of the rear portion, with a tread layer of relatively soft, especially rubber-like, material, which together with the associated outsole portions defines a predetermined overall sole thickness or sole height.
2. Description of Related Art
Outsoles of such a kind are generally known. For example, they have been manufactured and sold by the Applicant under the Trade Mark “NNN” for years. Those outsoles have, on the tread side, two longitudinal guidance grooves and also transverse grooves which are connected thereto, the longitudinal guidance grooves extending over the entire length of the sole and co-operating with complementary longitudinal guidance ribs on an associated ski-binding plate. At the front end of the sole, on the tread side, there is provided within a recess provided on the tread side a transverse pin for articulated connection to a ski binding, the articulation being such that the shoe heel can be lifted up freely.
On the side of the upper, the outsole is provided with longitudinal and transverse ribs which bound corresponding recesses with the result that maximum stability, especially torsional stability, is obtained with a minimal use of material. The afore-mentioned longitudinal guidance grooves are formed not only within the tread layer but also within the outsole itself. As a result, the bending elasticity is considerably impaired, especially in the metatarsophalangeal region of the outsole. In order to solve that problem, EP 0 787 440 B1 proposes that the outsole of a sports shoe be produced from two parts, the rear part being of rigid construction and the front part being made from a soft material. A disadvantage of such an arrangement, however, is that the sole cannot be produced so as to be continuously of one and the same material, for example by means of injection-moulding. The cost of sole manufacture is therefore disproportionately high, with EP 0 787 440 B1 also proposing in that regard that the front and rear parts each be joined to the other with an overlap.
The present invention is accordingly based on the problem of so developing an outsole of the kind mentioned at the beginning that, by simple manufacturing means, a sole having maximum bending elasticity in the metatarsophalangeal region is obtained without the lateral, especially torsional, stability of the sole and of the upper connected thereto being lost as a result of the chosen construction.